This site allows you to create a virtual classroom. At our online school, we are provided with a virtual classrom through Elluminate. They do also offer a 3 for free which means you canhave your own room and have up to 3 people in at a time. This would be great for online tutoring sessions. You can upload PowerPoints to the whiteboard to help students understand a topic.

Elluminate is an online collaboration system that allows a live synchronous classroom session, chat, voice, interactive whiteboard, surveys, and quizzes. Teachers can sign up for a free online meeting room for up to three participants (a participant is a connection to another classroom).